import React from 'react';
import { useParams } from 'react-router-dom';
import { YStack, XStack } from '@tamagui/stacks';
import { SizableText as Text } from '@tamagui/text';
import { Button } from '@tamagui/button';
import { AlertCircle, Download } from 'lucide-react';
import StandaloneShell from '../components/StandaloneShell';
import SurfaceCard from '../components/SurfaceCard';
import EventLogo from '../components/EventLogo';
import { fetchPhotoShare } from '@/guest/services/photosApi';
import type { EventBrandingPayload } from '@/guest/services/eventApi';
import { useTranslation } from '@/guest/i18n/useTranslation';
import { EventBrandingProvider } from '@/guest/context/EventBrandingContext';
import { mapEventBranding } from '../lib/eventBranding';
import { BrandingTheme } from '../lib/brandingTheme';
import { useGuestThemeVariant } from '../lib/guestTheme';

interface ShareResponse {
  slug: string;
  expires_at?: string;
  photo: {
    id: number;
    title?: string;
    likes_count?: number;
    emotion?: { name?: string; emoji?: string | null } | null;
    created_at?: string | null;
    image_urls: { full: string; thumbnail: string };
  };
  event?: { id: number; name?: string | null } | null;
  branding?: EventBrandingPayload | null;
}

export default function SharedPhotoScreen() {
  const { slug } = useParams<{ slug: string }>();
  const { t } = useTranslation();
  const [state, setState] = React.useState<{ loading: boolean; error: string | null; data: ShareResponse | null }>({
    loading: true,
    error: null,
    data: null,
  });
  const branding = React.useMemo(() => {
    if (!state.data?.branding) {
      return null;
    }
    return mapEventBranding(state.data.branding);
  }, [state.data]);
  const { isDark } = useGuestThemeVariant(branding);
  const mutedText = isDark ? 'rgba(248, 250, 252, 0.7)' : 'rgba(15, 23, 42, 0.65)';

  React.useEffect(() => {
    let active = true;
    if (!slug) return;
    setState({ loading: true, error: null, data: null });

    fetchPhotoShare(slug)
      .then((data) => {
        if (active) setState({ loading: false, error: null, data });
      })
      .catch(() => {
        if (active) {
          setState({
            loading: false,
            error: t('share.expiredDescription', 'Dieser Link ist nicht mehr verfügbar.'),
            data: null,
          });
        }
      });

    return () => {
      active = false;
    };
  }, [slug]);

  if (state.loading) {
    return (
      <StandaloneShell>
        <SurfaceCard>
          <Text fontSize="$3" color={mutedText}>
            {t('share.loading', 'Moment wird geladen …')}
          </Text>
        </SurfaceCard>
      </StandaloneShell>
    );
  }

  if (state.error || !state.data) {
    return (
      <StandaloneShell>
        <SurfaceCard>
          <XStack alignItems="center" gap="$2">
            <AlertCircle size={18} color={isDark ? '#FCA5A5' : '#B91C1C'} />
            <Text fontSize="$4" fontWeight="$7">
              {t('share.expiredTitle', 'Link abgelaufen')}
            </Text>
          </XStack>
          <Text fontSize="$2" color={mutedText} marginTop="$2">
            {state.error ?? t('share.expiredDescription', 'Dieses Foto ist nicht mehr verfügbar.')}
          </Text>
        </SurfaceCard>
      </StandaloneShell>
    );
  }

  const { data } = state;
  const chips = buildChips(data, t);

  const content = (
    <StandaloneShell>
      <SurfaceCard glow>
        <XStack alignItems="center" gap="$3">
          <EventLogo name={data.event?.name ?? t('share.defaultEvent', 'Ein besonderer Moment')} size="s" />
          <YStack gap="$1">
            <Text fontSize="$2" letterSpacing={2} textTransform="uppercase" color={mutedText}>
              {t('share.title', 'Geteiltes Foto')}
            </Text>
            <Text fontSize="$6" fontWeight="$8">
              {data.event?.name ?? t('share.defaultEvent', 'Ein besonderer Moment')}
            </Text>
          </YStack>
        </XStack>
        {data.photo.title ? (
          <Text fontSize="$3" color={mutedText} marginTop="$1">
            {data.photo.title}
          </Text>
        ) : null}
      </SurfaceCard>

      <SurfaceCard padding={0} overflow="hidden">
        <YStack
          height={360}
          style={{
            backgroundImage: `url(${data.photo.image_urls.full})`,
            backgroundSize: 'cover',
            backgroundPosition: 'center',
          }}
        />
      </SurfaceCard>

      {chips.length > 0 ? (
        <XStack gap="$2" flexWrap="wrap" justifyContent="center">
          {chips.map((chip) => (
            <SurfaceCard key={chip.id} padding="$2" borderRadius="$pill">
              <XStack alignItems="center" gap="$2">
                {chip.icon ? <Text fontSize="$3">{chip.icon}</Text> : null}
                <Text fontSize="$2" color={mutedText}>
                  {chip.label}
                </Text>
                <Text fontSize="$2" fontWeight="$7">
                  {chip.value}
                </Text>
              </XStack>
            </SurfaceCard>
          ))}
        </XStack>
      ) : null}

      <Button
        size="$4"
        borderRadius="$pill"
        backgroundColor="$primary"
        onPress={() => window.open(data.photo.image_urls.full, '_blank')}
      >
        <Download size={18} color="white" />
        <Text fontSize="$3" fontWeight="$7" color="white">
          {t('galleryPublic.download', 'Download')}
        </Text>
      </Button>
    </StandaloneShell>
  );

  if (!branding) {
    return content;
  }

  return (
    <EventBrandingProvider branding={branding}>
      <BrandingTheme>
        {content}
      </BrandingTheme>
    </EventBrandingProvider>
  );
}

function buildChips(
  data: ShareResponse,
  t: (key: string, fallback?: string) => string
): { id: string; label: string; value: string; icon?: string }[] {
  const list: { id: string; label: string; value: string; icon?: string }[] = [];
  if (data.photo.emotion?.name) {
    list.push({
      id: 'emotion',
      label: t('share.chips.emotion', 'Emotion'),
      value: data.photo.emotion.name,
      icon: data.photo.emotion.emoji ?? '★',
    });
  }
  if (data.photo.title) {
    list.push({ id: 'task', label: t('share.chips.task', 'Aufgabe'), value: data.photo.title });
  }
  if (data.photo.created_at) {
    const date = formatDate(data.photo.created_at);
    list.push({ id: 'date', label: t('share.chips.date', 'Aufgenommen'), value: date });
  }
  return list;
}

function formatDate(value: string): string {
  const parsed = new Date(value);
  if (Number.isNaN(parsed.getTime())) return '';
  return parsed.toLocaleDateString(undefined, { day: '2-digit', month: 'short', year: 'numeric' });
}